Belt grinding machines and platen therefor

ABSTRACT

A platen includes a narrow pressure strip of a hard material rigidly mounted on a supporting portion of the platen. The grinding machine utilizing the platen is the type in which work is fed in a direction normal to the movement of the abrasive belt. The platen is rigidly tensioned against the abrasive belt so that narrow pressure portion urges the abrasive belt against a workpiece.

United States Patent CoPresti [1 1 3,686,798 [451 Aug. 29, 1972 [72]inventor: Charles CoPresti, 1064 99th St.,

Niagara Falls, NY. 14304 [73] Assignee: The Carborundnm Company, NiagaraFalls, N.Y.

[22] Filed: Nov. 16, 1970 [21] Appl. No.: 89,680

[52] US. Cl. ..51/l38, 51/141, 51/148 [51] Int. Cl ..B24b 21/08, B24b21/10 [58] Field of Search.....5l/l37, 138,141,103 R, 148

[56] References Cited UNITED STATES PATENTS 1,924,593 8/1933 Binns .51]103 R 1,978,149 10/1934 Stevenson; ..5l/141 X 2,762,173 9/1956 Bottcher..5l/ 138 X 2,717,422 9/1955 Rowe... ..51/l41 X 2,651,150 9/1953Florez...... ..51/138 FOREIGN PATENTS 0R APPLICATIONS 924,256 2/1955Germany ..5 1 1 38 Primary Examiner-Donald 0. Kelly Attorney-K. W.Brownell ABSTRACT A platen includes a narrow pressure strip of a hardmaterial rigidly mounted on a supporting portion of the platen. Thegrinding machine utilizing the platen is the type in which work is fedin a direction normal to the movement of the abrasive belt. The platenis rigidly tensioned against the abrasive belt so that narrow pressureportion urges the abrasive belt against a workpiece.

5Claims,4DrawingFigures BACKGROUND OF THE INVENTION In belt sanding andpolishing machines of a known type, an endless abrasive belt is trainedabout a plurality of rollers and a platen is rigidly mounted above theactive run of the abrasive belt for urging the belt the purposes forwhich they were designed, they have not performed satisfactorily underall conditions of operations. In the processing of full-bodiedmaterials, such as bar stock, sheet stock or in the processing of veryhard ferrous materials, such as high carbon steel, these platens havecaused overheating, even with the flood of coolant, with the result thatcenter areas of the object being ground are often burned and distorted.An additional problem is the accumulation of grinding dust between thebelt and the workpiece which makes the belt blunt and ineffective.Furthermore, unless the square or rectangular platen is at a properangle with respect to the workpiece, so that the leading edge is abovethe trailing edge, the belt will wear unevenly. Adjusting platens of theprior art is often a time consuming trial and error process.

I-leretofore, platens of the prior art have not been effective inaggressively removing stock to produce a uniform surface while acheivingan even wear of the abrasive belt.

SUMMARY OF THE PRESENT INVENTION It is an object of the presentinvention to provide a new and improved platen for a belt grindingmachine.

It is another object of the present invention to provide a grindingmachine with an improved platen which removes stock aggressively withoutmarring the finished surface of the workpiece.

It is yet another object of the present invention to provide a new andimproved platen which is simple and strong in construction, effective inprolonging the life of the abrasive belt, and rugged and durable in use.

These and other objects of this invention will become more apparent uponconsideration of the following description thereof.

In accordance with the present invention, there is provided a platen fora belt grinding machine comprising a supporting portion and a pressingportion rigidly mounted on said supporting portion, said pressingportion comprising a narrow strip of wear resistant material adapted toextend obliquely across the width of the belt for urging the beltagainst a workpiece.

Also in accordance with the present invention, there is provided agrinding machine utilizing the aforementioned platen.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l illustrates the platen assemblyas employed in.

a grinding machine;

FIG. 2 is a front elevational view of mounting;

FIG. 3 is a side view of the platen; and

FIG. 4 is an end view of the platen of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings in moredetail, and particularly to FIG. 1, it can be observed that in apreferred embodiment of this invention the belt grinding machine 11includes a grinding head 13 mounted on a base 15. Adrive roller 17 ismounted on the grinding head 13 for rotation in suitable bearing meansand driven by an electric motor (not shown). Idler roller 19 ishorizontally spaced from the drive roller 17 and is mounted for rotationbetween two spaced arms of yoke member 21 which is mounted on thegrinding head 13. Tracking roller 23 is vertically spaced from the driveroller and similarly mounted on yoke member 25. The bight portion ofyoke member 25 is connected to one end of a fluid power device or fluidcylinder 27. The other end of the fluid cylinder 27 is connected to arm29 rigidly mounted on the grinding head I3. Actuation of the fluidcylinder 27 acts to apply tension to an abrasive belt 31 which istrained around rollers l7, l9 and 23.

The grinding-head I3 is positioned above a conveyor 33 so that work 35is fed into the abrasive belt 31 in a direction normal to the movementof the abrasive belt 31. To permit convenient grinding of workpieces ofvarying thickness, the distance between the abrasive belt 31 and theconveyor 33 may be selectively varied. It is contemplated that thisadjustment may be achieved by various conventional means. For example,the grinding head 13 can be supported for vertical movement by utilizinga pair of split tapered gibs attached to the backside thereof. The gibsslide vertically in square ways in a pair of columns firmly mounted tothe base 15 or floor. A screw jack can be used to raise or lower thegrinding head 13. In another arrangement for adjusting the grindingmachine to accomodate different workpieces, the conveyor may beselectively raised or the platen lowered by screw jacks while thegrinding head remains rigidly mounted to supporting members. Since manysuch arrangementsof grinding head and conveyor are known in the priorart, no illustration or further explanation is believed necessary.

As illustrated in FIG. 1, the conveyor 33 which feeds work 35 in adirection indicated by the arrow is of a conventional type. The conveyor33 includes a conveyor frame 37 which is provided with rollers 39journaled for rotation at opposite ends thereof. An endless conveyorbelt 4l advances the workpieces beneath the abrasive belt 31. Theconveyor belt 41 is driven by any suitable means, such as an electricmotor, at a selected speed.

A pair of platen support members 43 which have flat mounting surfaces 45facing the conveyor belt 41 project outwardly from the grinding head 13.The support members 43 are preferably a pair of angle irons each havingone side secured to the grinding head 13 with another side projectingover the conveyor belt 41. A plate 47 is rigidly mounted to the mountingsurfaces 45. A plurality of bores 49 in the mounting surfaces 45 arealigned with bores 51 in the backing plate 47. Bolts 53 passing throughbores 49 and bores 51 secure the plate 47 to mounting surface 45. Theplate 47 is preferably adjusted so as to lie in a plane parallel to thework supporting surface of the conveyor belt 41 by utilizing spacingmembers 55 around the bolts 53. The spacing members 55 are positionedbetween the plate 47 and the mounting surface 45.

The platen 57 is rigidly positioned above the conveyor belt 41 andtensioned against the non-abrasive side of the abrasive belt 31. Theheight of the platen above the conveyor is varied depending upon theamount of stock removal desired or the precise dimension of theworkpiece desired.

The platen 57 comprises a supporting portion 59 in the shape of anelongated rectangular bar. The top surface 61 of the supporting portion59 is rigidly secured to the bottom of plate 47. Preferably bolts 63pass through holes 65 in the plate 47 and engage threaded holes 67 inthe top surface of the supporting portion 59.

According to the principles of the present invention as illustrated in apreferred embodiment, the bar platen 57 comprises a pressing portion 69which is a narrow strip of wear resistant material extending lengthwiseof the platen and projecting downwardly from the bottom surface of thesupporting portion 59. Preferably the pressing portion is a strip ofuniform width with a bottom surface aligned in a plane substantiallyparallel to the work conveying surface. Most preferably a singlepressing portion of less than about one inch in width is employed so asto achieve an agressive grinding action while minimizing overheating ofthe work and accumulation of detritus.

The pressing portion 69 is preferably an insert of a hard, dense wearresistant material such as tungsten carbide. As illustrated in FIG. 4,the supporting portion 59 includes a rectangular recess or slot 73extending lengthwise and positioned in the widthwise center of thebottom surface of the supporting portion 59. A plurality of laterallybored holes 75 are aligned with the slot 73 and extend through one sideof the supporting portion 59. Threaded holes 77 in the insert arealigned with holes 75. Bolts 79 or other suitable fastening means passesthrough the respective holes in the supporting portion 59 and the insert71 to hold the insert in a fixed position.

The pressing portion 69 extends lengthwise across the entire width ofthe abrasive belt 31 and coversthe entire width of the surface to beground. The pressing portion 69 can be mounted substantiallyperpendicular to the direction of movement of the belt to grind verynarrow work surfaces or be mounted obliquely to grind wider worksurfaces.

The conveyor 33 is conveniently provided with a fence 81 which maintainsthe position of the work 35 on theconveyor belt 41. The abrasive belt 31acts to drive the work into the fence 81. In some instances, whereirregularly shaped workpieces are being finished, it may be necessary toprovide bridging between the workpiece and the fence to maintain theproper position of the workpiece during grinding.

In operation, the grinding head is adjusted to the proper height abovethe conveyor belt 41 so as to achieve the removal of the proper amountof stock from the workpiece. The platen 57 is mounted so that the insert71 extends across the belt and covers the entire width of the surface tobe ground. workpieces are seamst ess r. strata. tits. as: $.22: into theabrasive belt 31 they are subjected to the grinding action. A nozzle canbe employed to direct a stream of coolant between the abrasive belt andthe workpiece to lubricate and cool the contacting surfaces.

A preferred embodiment of this invention having been described and.illustrated, it is to be realized that modifications thereof may be madewithout departing from the broad spirit and scope of this invention asdescribed in the appended claims.

What is claimed is:

l. A grinding machine comprising a grinding head, a plurality of rollsmounted for rotation on said grinding head, an abrasive belt carried bysaid rolls and having an active run, a platen, means having a workconveying surface for feeding work into said abrasive belt and undersaid platen in a direction normal to the movement of said belt, meansfor rigidly mounting said platen above the active run of said abrasivebelt, said platen comprising a supporting member and a single narrowpressing member rigidly mounted to said supporting member, said pressingmember being of uniform width and having a bottom surface in a planesubstantially parallel to the work conveying surface, said pressingmember being adapted to be tensioned against said abrasive belt andextending obliquely across the width thereof.

2. A grinding machine according to claim 6 wherein said pressing meanscomprises a hard wear resistant material.

3. A grinding machine according to claim 2 wherein said pressing portioncomprises an insert strip.

4. A grinding machine according to claim 3 wherein said pressing portionis less than about 1 inch in width.

5. A grinding machine according to claim 4 including a backing plate forsecuring said supporting member to said grinding head, said backingplate being adjustably attached to said support member.

1. A grinding machine comprising a grinding head, a plurality of rollsmounted for rotation on said grinding head, an abrasive belt carried bysaid rolls and having an active run, a platen, means having a workconveying surface for feeding work into said abrasive belt and undersaid platen in a direction normal to the movement of said belt, meansfor rigidly mounting said platen above the active run of said abrasivebelt, said platen comprising a supporting member and a single narrowpressing member rigidly mounted to said supporting member, said pressingmember being of uniform width and having a bottom surface in a planesubstantially parallel to the work conveying surface, said pressingmember being adapted to be tensioned against said abrasive belt andextending obliquely across the width thereof.
 2. A grinding machineaccording to claim 6 wherein said pressing means comprises a hard wearresistant material.
 3. A grinding machine according to claim 2 whereinsaid pressing portion comprises an insert strip.
 4. A grinding machineaccording to claim 3 wherein said pressing portion is less than about 1inch in width.
 5. A grinding machine according to claim 4 including abacking plate for securing said supporting member to said grinding head,said backing plate being adjustably attached to said support member.